Infrastructure

Power & Networking

Why miners want 240V not 110V, breaker math, plug types, and the IP/VLAN/DNS scheme that keeps a fleet reachable.

The power chain (utility -> miner)

Power steps down through several stages before it reaches a miner. Knowing the chain tells you where a fault lives.

Utility/substation (kV) -> TRANSFORMER (steps down to 208/240/415 V - the most critical piece) -> SWITCHGEAR (main breakers/metering) -> sub-panel/PDU -> POWER WHIP (the liquid-tight cable to the PDU) -> miner PSU.
A Delta-Wye transformer provides the neutral; K-factor rated (K-13+) handles the harmonics miner PSUs create.
Balance miners evenly across all three phases of a 3-phase PDU - an unbalanced phase overloads.

Voltage, phase and power factor: use the exact rating

Use only an OEM-approved supply. For single-phase AC, P = V × I × PF; at constant real power and power factor, doubling voltage halves current. The table assumes PF = 1 and is an estimate, not installation sizing. Balanced three-phase total power uses P = √3 × V(line-line) × I × PF. Follow rated maximum input-current and installation requirements; qualified measurements supplement them.

A 3,250 W miner draws ~15.6 A at 208 V but only ~13.5 A at 240 V - less current, less heat, more miners per breaker.
PSU efficiency varies with model, supply and load; use its documented efficiency curve rather than a universal percentage.
C13/C19 cords are rated to 250 V max - true 277 V needs special cords/PDUs.
120 V to a miner = underperformance, no-boot, or power/hashboard faults. They are NOT 110 V devices.

Miner draw	@208 V	@240 V	@277 V
3,000 W	14.4 A	12.5 A	10.8 A
3,250 W	15.6 A	13.5 A	11.7 A
3,500 W	16.8 A	14.6 A	12.6 A

Plugs & the 80% breaker rule

In the standard-rated NEC-style continuous-load example, load is limited to 80% of breaker rating (125% sizing). Properly applied 100%-rated assemblies and local rules can differ; qualified design must also cover conductors and equipment.

Breaker continuous capacity: 20 A -> 16 A, 30 A -> 24 A, 50 A -> 40 A.
One ~3.25 kW/240 V miner (~13.5 A) fits a 20 A circuit. Two large miners on a 30 A (27 A) is NOT allowed (>24 A).
Stagger power-ons - inrush current on a whole rack at once trips breakers.

Connector	Rating	Use
C13 / C14	250 V, ~15 A	Standard miner cord
C19 / C20	250 V, ~20 A	Modern high-watt ASICs
NEMA L6-30	250 V, 30 A	Twist-lock PDU (vibration-proof)
IEC 60309	16-60 A 3Ø	Industrial PDU feeds

Networking: IP scheme, VLAN, DNS

A fleet needs a stable, isolated network where every miner maps to a physical location.

Use private IPs (10.x / 172.16.x / 192.168.x). A /24 = 254 hosts; a /16 = 65,534 in one flat L2 so one scan reaches all.
Encode location in the IP: 10.<row>.<rack>.<position> - the #1 farm IP principle. Keep IP<->location stable with static IPs or DHCP reservations.
Put miners on their own management VLAN, isolated from office/internet, for security and broadcast control.
Same-L2 requirement: the Antminer IP-report is a UDP BROADCAST - it never crosses a router, so a different subnet = IP-report always fails.
Ports: 80 web UI · 4028 mining API · 22 SSH · 333x Stratum out to the pool.
DNS kills pools: miners resolve the pool hostname before Stratum can start. Bad DNS = 'pool connection failed' even though the web UI loads. Fix with 8.8.8.8 / 1.1.1.1.

The power chain (utility -> miner)

Power steps down through several stages before it reaches a miner. Knowing the chain tells you where a fault lives.

Utility/substation (kV) -> TRANSFORMER (steps down to 208/240/415 V - the most critical piece) -> SWITCHGEAR (main breakers/metering) -> sub-panel/PDU -> POWER WHIP (the liquid-tight cable to the PDU) -> miner PSU.

A Delta-Wye transformer provides the neutral; K-factor rated (K-13+) handles the harmonics miner PSUs create.

Balance miners evenly across all three phases of a 3-phase PDU - an unbalanced phase overloads.

Voltage, phase and power factor: use the exact rating

A 3,250 W miner draws ~15.6 A at 208 V but only ~13.5 A at 240 V - less current, less heat, more miners per breaker.

PSU efficiency varies with model, supply and load; use its documented efficiency curve rather than a universal percentage.

C13/C19 cords are rated to 250 V max - true 277 V needs special cords/PDUs.

120 V to a miner = underperformance, no-boot, or power/hashboard faults. They are NOT 110 V devices.

Miner draw	@208 V	@240 V	@277 V
3,000 W	14.4 A	12.5 A	10.8 A
3,250 W	15.6 A	13.5 A	11.7 A
3,500 W	16.8 A	14.6 A	12.6 A

Plugs & the 80% breaker rule

Breaker continuous capacity: 20 A -> 16 A, 30 A -> 24 A, 50 A -> 40 A.

One ~3.25 kW/240 V miner (~13.5 A) fits a 20 A circuit. Two large miners on a 30 A (27 A) is NOT allowed (>24 A).

Stagger power-ons - inrush current on a whole rack at once trips breakers.

Connector	Rating	Use
C13 / C14	250 V, ~15 A	Standard miner cord
C19 / C20	250 V, ~20 A	Modern high-watt ASICs
NEMA L6-30	250 V, 30 A	Twist-lock PDU (vibration-proof)
IEC 60309	16-60 A 3Ø	Industrial PDU feeds

Networking: IP scheme, VLAN, DNS

A fleet needs a stable, isolated network where every miner maps to a physical location.

Use private IPs (10.x / 172.16.x / 192.168.x). A /24 = 254 hosts; a /16 = 65,534 in one flat L2 so one scan reaches all.

Encode location in the IP: 10.<row>.<rack>.<position> - the #1 farm IP principle. Keep IP<->location stable with static IPs or DHCP reservations.

Put miners on their own management VLAN, isolated from office/internet, for security and broadcast control.

Same-L2 requirement: the Antminer IP-report is a UDP BROADCAST - it never crosses a router, so a different subnet = IP-report always fails.

Ports: 80 web UI · 4028 mining API · 22 SSH · 333x Stratum out to the pool.

DNS kills pools: miners resolve the pool hostname before Stratum can start. Bad DNS = 'pool connection failed' even though the web UI loads. Fix with 8.8.8.8 / 1.1.1.1.